The repair work of old, deteriorated pipe lines with a purpose of fixing cracks and fissures developed in the pipes is currently generally effected by using a flexible material to be laid on the inner surface of pipes, said material including a curing agent as well as a necessary reinforcement layer for providing strength. Such material is generally laid in underground pipe lines from above the ground as a long tubular sleeve in a manner that the pipes need not be dug up. Such a method is known e.g. as "Insituform" or "Paltem" and it is in a wide-spread use.
The material inserted inside a pipe line is required to have a particularly good flexibility, plasticity and strength and, thus, it has been difficult to find proper materials. In addition, since pipes come in varying sizes and often include sharp bends, flexibility and plasticity are particularly important factors in a lining and repair material.